countable sets

I need some help with this proof:

Let C be a countable set. Prove C^n is countable for all n.

I was thinking to show that the Cartesian product of any countable sets is countable by writing them out in a table and going through the elements diagonally to count them, similar to a proof I have seen to show that the rational numbers are countable.

this proves C^2 is countable since C is countable.
then using induction I can say that C^n+1 is countable because it = C^n (which is countable from the induction premise) x C and is therefore the cartesian product of two countable sets.